President's Address. 



323 



associated with the bones and tusks and horns of these ex- 

 tinct mammalia. But these implements (like those of 

 Abbeville, &c.) are often found at great depths, and at alti- 

 tudes above the levels of existing rivers that prove the 

 occurrence of great physical changes in these regions ; and 

 this, taken in conjunction with the extinction of the mam- 

 malia and the evident amelioration in climate, bespeaks a 

 vast antiquity compared with the shell-mounds and pile- 

 dwellings of the preceding races. A vast antiquity! but 

 whether ten, twelve, or twenty thousand years, we have in 

 the mean time no mode of precisely determining. 



Physical changes proceed at rates too uncertain to con- 

 stitute a scale of chronology, and we know too little of the 

 law of vital development to found upon the duration and 

 extinction of species. But if we may judge from existing 

 operations, and if we may estimate from the specific changes 

 in life now going on around us (and this with all the inter- 

 fering influences imposed by man), then the time must be 

 vast indeed since these primitive races were the inhabitants 

 of Southern and Western Europe. We do not contend, like 

 some, for thousands of centuries ; but we argue for triple or 

 quadruple the amount that has hitherto been assigned to 

 human chronology. Let us look fairly at the facts: the 

 river-drifts, cave-earths, and lake-silts are, no doubt, very 

 ancient, but there is nothing connected therewith that may 

 not (computing by existing operations) have been accom- 

 plished in ten or twelve thousand years. Again, the mam- 

 moth, woolly rhinoceros, cave-lion, cave-bear, and cave-hyena, 

 are but species of existing genera ; and so little do they 

 vary in general character from those still living, that their 

 appearance at the present day would excite no marvel. The 

 whole aspects and surroundings of these extinct mammalia 

 are in truth geologically recent ; and when we further con- 

 eider the fresh condition in which some of them occur in 

 the ice-gravels of Siberia, w r e are compelled to withhold 

 from them an unlimited antiquity. It is a sound maxim in 

 palaeontology, that the greater the divergence of any species 

 from existing species, the greater its antiquity ; and found- 

 ing on this rule, the mammoth, mastodon, and their huge 



